Good video on PV grounding
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timselectric
If I can do it, you can do it.
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Hopefully this will help people understand.
This is going to save me from explaining it over and over.
This is going to save me from explaining it over and over.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
BTW: One thing the video did not go into was talking about why NOT to do an auxiliary grounding electrode for the PV array.
timselectric
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No, but he covers it in other videos.
If someone wants to know why.
It doesn't only pertain to solar installations.
It was an issue before solar got popular.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Zwy
Emperor Of Solar
The steel pole 8.5 feet in the ground, wrapped in concrete. I'd use a plastic pole but they don't seem to make one that can handle it.
Yes, this does have a grounding electrode conductor from the PV array to the house grounding system.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Yes, With ground-mounted arrays, it can be difficult to avoid a 2nd earth grounding point. In this situation, I run the EGC from the array directly to the main breaker box where the system grounding jumper goes to the grounding electrodes. This keeps the potential pulse away from all the solar electronics.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
BTW: The NEC makes a specific allowance for routing the EGC separately from the PV circuits. I suspect at least part of the reason for this is to allow the EGC to go directly to the common ground bus where the Grounding Jumper is.
Robkh
New Member
I have a 4000W ground mounted array >100 feet from the house. Even though NEC 690.47(A)(1) says that “the PV output circuit is the only connection to ground required for the PV system” do you recommend I still run 6AWG copper ground wire with my PV cables in a buried conduit to join with the earth ground bus bar at my house where the EG4 6000XP inverter resides?
I suspect that is the right thing to do to avoid potential differences as everything is connected to one earth ground.
I suspect that is the right thing to do to avoid potential differences as everything is connected to one earth ground.
Zwy
Emperor Of Solar
You do not need 6AWG, it can be sized to the amps carried by the PV current carrying conductors.
You are required to run a ground wire from array to house grounding system. That is the only ground wire needed, no auxillary ground rod.
AZ Solar Junkie
Maricopa, AZ
Good one to bookmark for sure
Robkh
New Member
Zwy
Emperor Of Solar
What size are the current carrying conductors? Usually one size down.
Exposed ground wires need to be 6AWG but once in a box or conduit it can be downsized.
I ran 10AWG to minimize voltage drop with a 420 foot run even though amperage is only about 12A. The ground wire is 10AWG, I just keep everything the same size usually. I could have used 12AWG.
timselectric
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Robkh
New Member
One more question regarding NEC 690.47(A)(1) - most PV systems are functionally grounded rather than solidly grounded. Mike Holt says that for functionally grounded systems, the inverter equipment grounding conductor is connected to the grounded distribution equipment. This connection is used for the ground-fault protection and for equipment grounding of PV array.
Additional grounding of the PV system is permitted but not required. This seems to suggest that attaching PV array ground to earth ground is not required.
However it doesn’t seem a big deal for me to connect the ground wire from the PV array to the earth ground before the PV cables enter the house. Also any ground faults would go directly to earth-ground instead of coursing through the inverter to the earth grounded distribution system.
Additional grounding of the PV system is permitted but not required. This seems to suggest that attaching PV array ground to earth ground is not required.
However it doesn’t seem a big deal for me to connect the ground wire from the PV array to the earth ground before the PV cables enter the house. Also any ground faults would go directly to earth-ground instead of coursing through the inverter to the earth grounded distribution system.
timselectric
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Or recommended.
Ground faults do not go to earth. They return to the source. (N/G bond)
Robkh
New Member
I forgot that the neutral ground bond clears the fault. My error. Thanks for clarifying Timselectric.
Zwy
Emperor Of Solar
What type of wire do you plan on using for direct burial?
I highly recommend using PVC conduit and one that is large enough you can add more wires later.
timselectric
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I wouldn't use bare. But if your ground mount is made of metal posts in the earth, it really doesn't matter.
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